The absolute configuration of the dextrorotatory meta-hydroxylated metabolite of diphenylhydantoin from dog urine will be investigated. The metabolism of diphenylhydantoin in patients showing hypersensitivity reactions will be studied. Studies of the biochemical effects of the ketogenic diet on the same brain will continue. Possible homolytic fission of the C-Br bond in halothane will be investigated. BIBLIOGRAPHIC REFERENCES: Butler, T.C., Dudley, K.H., Johnson, D., and Roberts, S.B.: Studies of the metabolism of 5,5-diphenylhydantoin relating principally to the stereoselectivity of the hydroxylation reactions in man and the dog. J. Pharmacol. Exp. Ther. 199, 82-92 (1976). Davidian, N.M., Butler T.C., and Pool, D.T.: Effects of Medium-chain triglycerides (MCT)-induced ketosis on blood and brain pH. Pharmacologist 18, 158 (1976). (Abstract).